Alkylhydroxyphenylcarboalkoxy substituted nitrogen heterocycles as stabilizers against oxidative thermal and photochemical degradation of organic materials

ABSTRACT

COMPOUNDS CONTAINING ONE OR MORE ALKYLHYDROXYPHENYL GROUPS BONDED THROUGH CARBOALKOXY LINKAGES TO A NITROGEN ATOM OF A HETEROCYCLIC NUCLEUS CONTAINING AN IMIDODICARBONYL   -(CO-NH-CO)-   GROUP OR AN IMIDODITHIOCABONYL   -(C(=S)-NH-C(=S))-   GROUP HAVE BEEN PREPARED AND ARE EXTREMELY EFECTIVE STABILIZERS AGAINST THE DELETERIOUS EFFECTS OF OXYGEN, HEAT AND LIGHT FOR ORGANIC MATERIALS. THE STABILITY OF POLYMERIC COMPOSITIONS SUCH AS A-OLEFIN POLYMERS AND COPOLYMERS, ACETAL POLYMERS, POLYAMIDES, POLYESTERS AND POLYURETHANES IS MARKEDLY INCREASED BY THE ADDITION OF SMALL AMOUNTS OF THE COMPOUNDS THERETO.

United States Patent 3,763,093 ALKYLI-IYDROXYPHENYLCARBOALKOXY-SUB-STITUTED NITROGEN HETEROCYCLES AS STABILIZERS AGAINST OXIDATIVE, THER-MAL AND PHOTOCHEMICAL DEGRADATION OF ORGANIC MATERIALS George Kletecka,Lakewood, and Peter D. Smith, Cleveland, Ohio, assignors to The B. F.Goodrich Company No Drawing. Original application Apr. 27, 1970, Ser.No. 32,435, now Patent No. 3,531,483. Divided and this application Feb.10, 1972, Ser. No. 225,341

Int. Cl. C08f 45/60 US. Cl. 260-453 N 17 Claims ABSTRACT OF THEDISCLOSURE Compounds containing one or more alkylhydroxyphenyl groupsbonded through carboalkoxy linkages to a nitrogen atom of a heterocyclicnucleus containing an group or an imidodithiocarbonyl group have beenprepared and are extremely effective stabilizers against the deleteriouseffects of oxygen, heat and light for organic materials. The stabilityof polymeric compositions such as a-olefin polymers and copolymers,acetal polymers, polyamides, polyesters and polyurethanes is markedlyincreased by the addition of small amounts of the present compoundsthereto.

This is a division of application Ser. No. 32,435 filed Apr. 27, 1970,now US. Pat. 3,531,483.

BACKGROUND OF THE INVENTION Esters of nitrogen heterocycles containingthe imidodicarbonyl or imidodithiocarbonyl molecular groupings areknown, however, the ester substituents have typically been limited tothe more common aliphatic hydrocarbon radicals containing up to about 8carbon atoms. Arylsubstituted isocyanurates have been prepared but havegenerally been limited to functionally unsubstituted isocyanurates, thatis where the aromatic nuclei contain no substitution. In a copending US.patent application Ser. No. 770,863 now US. Pat. 3,531,483, arylisocyanurates wherein the aryl substituent is functionally substitutedwith a hydroxyl group were prepared. The hydroxyaryl group was bonded tothe isocyanurate nucleus by a methylene (CH linkage. It would bedesirable to have isocyanurates and structurally related heterocycliccompounds substituted with one or more hydroxyaryl groups wherein thehydroxyaryl groups are bonded to the isocyanurate or other heterocyclicnucleus through an ester-type linkage.

SUMMARY OF THE INVENTION We have now prepared compounds containing oneor more alkylhydroxyphenyl groups bonded through carboalkoxy linkages toa nitrogen atom of a heterocyclic nucleus containing imidodicarbonyl orimidodithiocarbonyl molecular groupings in the ring. Preferably thealkylhydroxyphenyl group will contain alkyl substitution and morepreferably tertiary alkyl groups containing from 4 to 8 carbon atomsimmediately adjacent to the hydroxy group on the benzene ring. The totalnumber of carbon atoms making up the carboalkoxy linkage will be betweenabout 2 and 20. While a wide variety of heterocyclic com pounds mayserve as the nucleus for the compounds of the present invention, so longas they contain one or more imidodicarbonyl or imidodithiocarbonylmolecular groupings within the ring, excellent results are obtained whenisocyanuric acid serves as the nucleus and is substituted with one, twoor three alkylhydroxyphenyl groups.

The present alkylhydroxyphenylcarboalkoxy-substituted nitrogenheterocycles are useful stabilizers for a wide variety of organicmaterials. They are extremely effective protective agents for organicpolymeric materials, both natural and synthetic, which are subject tothe deleterious effects of oxygen, heat and ultraviolet or visiblelight. They are especially useful as stabilizers for o: olefin polymersand copolymers, acetal polymers, polyamides, polyesters andpolyurethanes.

DETAILED DESCRIPTION groups or imidodithiocarbonyl (iii) groups. Thecompounds of the present invention are represented by the generalformula x I; R R r r I g r 1 0H AL N LCnHZnJ L m hJ if R R X (I) wherinn is an integer for 1 to 12, m is an integer from 0 to 8, R is hydrogenor a hydrocarbon radical containing from 1 to 12 carbon atoms, X isoxygen or sulfur and A is a bivalent molecular grouping. The bivalentradical A may be a hydrocarbon radical, such as alkylene or phenylene,or may contain one or more heteroatoms or other functional groups, suchas NH, C=S,

or the like. In the latter instance where more than one NH group ispresent in the ring it will be possible to prepare compounds containinga plurality of alkylhydroxyphenyl groups. While R is preferably hydrogenor a hydrocarbon radical, it may be any other group capable of beingsubstituted on an aromatic ring, such as halogen or a nitro group.Compounds of Formula I which are especially useful for the presentinvention are those wherein X is oxygen, n is an integer from 1 to 8, mis an integer from 1 to 4 and the hydroxyl group is in the 4-position onthe ring and is hindered, i.e., has positioned on the ring immediatelyadjacent thereto at least one alkyl group containing from 1 to 12 carbonatoms.

The nitrogen heterocycle serves as the nucleus for attachingalkylhydroxyphenyl groups of the formula wherein R is the same asdefined for Formula I. So long as the heterocyclic compound contains oneor more nitrogen atoms in the ring with two carbonyl or thiocarbonylgroups immediately adjacent thereto such as o o H s Aisha, -333 t l tthe heterocyclic compound can be suitably substituted for the purposesof the present invention. Heterocyclic compounds useful for thesubstitution of one or more alkylhydroxyphenyl groups thereon includeuric acid, hydantoin, allantoin, parabanic acid, alloxan, uracil,thymine, barbituric acid, phenobarbitone, isocyanuric acid, succinimideand maleimide and derivatives thereof, phthalimide and derivativesthereof, and similar structurally related materials. With certainheterocyclic compounds such as barbituric acid and isocyanuric acid, forexample, where the ring contains more than one nitrogen atom having twocarbonyl or thiocarbonyl groups immediately adjacent thereto, it ispossible for a plurality of alkylhydroxyphenyl groups to be substituted.For example, two alkylhydroxyphenyl groups could be substituted on thebarbituric acid nucleus and in the case of isocyanuric acid up to threealkylhydroxyphenyl groups could be substituted in accordance with thepresent invention. It is not necessary, however, in the case ofbarbituric acid or isocyanuric acid that all of the nitrogen atoms ofthe ring be substituted. It will suffice if only one nitrogen atom besubstituted in such a manner, the remaining nitrogen atoms of the ringbeing substituted with hydrogen or some other radical. A wide variety ofstructural modifications are therefor possible with the compounds of thepresent invention.

A useful class of compounds for use as stabilizers for organicmaterials, particularly polymeric materials, are the derivatives ofisocyanuric acid. These compounds contain one or more alkylhydroxyphenylgroups bonded to the isocyanuric acid nucleus through a carboalkoxylinkage and have the structural formula wherein R is analkylhydroxyphenylcarboalkoxy group having the formula RR 1 r HOCTCmH2mT 111) wherein n, m and R are the same as defined for Formula Iabove; and R" and R' are the same as R or are hydrogen, a hydrocarbonradical containing from 1 to 20 carbon atoms such as alkyl, cycloalkyl,aryl, alkaryl or aralkyl, a hydroxyalkyl group containing from 1 to 12carbon atoms or an alkylcarboalkoxy group containing from 2 to 20 carbonatoms. Especially useful derivatives of isocyanuric acid are thosecompounds wherein two, and more preferably all, of the nitrogens of thering are substituted with radicals of the Formula III. Additionally, ithas been found that excellent results are obtained when thealkylhydroxyphenylcarboalkoxy group has the formula wherein n is aninteger from 1 to 8, m is an integer from 1 to 4, R is an alkyl groupcontaining from 1 to 8 carbon atoms, and R and R are hydrogen or alkylgroups containing from 1 to 8 carbon atoms. More preferably R is atertiary alkyl group containing from 4 to 8 carbon atoms, R is an alkylgroup containing from 1 to 8 carbon atoms and R is hydrogen. Anespecially preferred class of compounds of the present invention arethose wherein R, R and R of the "Formula II are alkylhydroxyphenylcarboalkoxy groups of Formula IV wherein n is an integer from 1 to 3, mis an integer from 1 to 3, R and R are tertiary alkyl groups containingfrom 4 to 8 carbon atoms and R is hydrogen. Excellent results areobtained with 2,2,2-tris[3(3,5-dit-butyl 4hydroxyphenyl)propionyloxy]ethylisocyanurate, alternatively named as3,5-di-t-butyl-4-hydroxyhydrocinnamic acid triester withl,3,5-tris(2-hydroxyethyl)- s-triazine-2,4,6(1H, 3H, 5H)-trione, whereinR, R" and R of Formula II are alkylhydroxyphenylcarboalkoxy groups ofFormula IV wherein n is 2, m is 2, R and R are t-butyl groups and R andR are hydrogen.

From the large number of compounds encompassed by the present invention,the following are intended only to be representative:

N-2- [3 (3,5 -di-t-butyl-4-hydroxyphenyl propionyloxy] ethylsuccinimide;

N-2- [3 (3 ,5 -di-t-butyl-4-hydroxyphenyl propionyloxy]ethylphthalirnide;

2,2',2"-tris 3 (3 ,5 -di-t-butyl-4-hydroxyphenyl) propionyloxy]ethyltrithioisocyanurate;

2,2',2"-tris 3 (3 ,5 -di-t-butyl-4-hydroxyphenyl propionyloxy]ethylisocyanurate;

2,2',2"-tris [3 (3-methyl-4-hydroxyphenyl) propionyloxy]ethylisocyanurate 2,2,2"-tris [3 (3-t-amyl-4-hydroxyphenyl propionyloxy]ethylisocyanurate 2,2,2"-tris [3 (3-octyl-4-hydroxyphenyl propionyloxy]ethylisocyanurate;

2,2',2"-tris 3 (3 ,5 -diisopropyl-4-hydroxyphenyl) propionyloxy]ethylisocyanurate 2,2,2"-tris [3 (3,5-dimethyl-4-hydroxyphenyl)propionyloxy] ethylisocyanurate;

2,2',2"-tris 3 3 ,5 -di-t-butyl-4-hydroxyphenyl) propionyloxy]methylisocyanurate;

2,2,2"-tris [3 (3 ,5 -di-t-butyl-4-hydroxyphenyl propionyloxy]-1-methylethylisocyanurate;

6,6,6-tris 3 3 ,5 -di-t-butyl-4-hydroxyphenyl) propionyloxy]hexylisocyanurate;

2- [3 (3 ,5 -di-t-butyl-4-hydroxyphenyl propionyloxy] 2,2"-bis (hydroxy)ethylisocyanurate;

2,2-bis 3 3 ,5 -di-t-butyl-4-hydroxyphenyl) propionyloxy] 2"- (hydroxyethylisocyanurate;

2,2-bis(octadecy1oxy)-2"-[3 (3 ,5 -di-t-butyl-4-hydroxyphenylpropionyloxy] ethylisocyanurate;

2,2-bis 3 3,5 -di-t-butyl4-hydroxyphenyl) propionyloxy] 2"- dodecyloxy)ethylisocyanurate;

2,2',2-tris 3 ,5 -di-t-butyl-4-hydroxybenzoyloxy) ethylisocyanurate;

2,2',2-tris [2-methyl-3 3,5 -di-t-butyl-4-hydroxyphenyl) propionyloxy]ethylisocyanurate and the like.

The alkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycles ofthe present invention are useful stabilizers for a wide variety oforganic materials. They are especially useful to prevent oxidative,thermal and photochemical degradation in polymeric materials, bothnatural and synthetic. The high degree of elfectiveness of the presentstabilizer compounds is attributed at least partially to their highmolecular Weight and excellent compatibility with most organicmaterials. The present compounds are also advantageous in that they arecapable of containing two or three alkylhydroxyphenyl substituents permolecule.

Organic materials stabilized in accordance with the present inventionincluude both natural and synthetic polymeric materials. The followingare representative of the polymers which can be effectively protected bythe addition of a stabilizing amount of analkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle thereto:homopolymers of ethylene, propylene, butene-l, isobutylene, pentene-l,hexene-l, 4-rnethylpentene-l and the like or copolymers thereof such asethylenepropylene copolymer, a copolymer of ethylene and butene-l, acopolymer of 4- methyl-l-pentene and hexene-l, and the like;ethylenepropylene terpolymers where the third monomer is a diene such as1,4-hexadiene, 2-methyl-l,4-hexadiene, a dimethyl- 1,4,9 decatriene,dicyclopentadiene, vinylcyclohexene, vinylnorbornene,ethylidenenorbornene, methylenenorbornene, norbornadiene,methylnorbornadiene, methyltetrahydroindene, and the like; polyacetalresins such as homopolymers obtained from the polymerization offormaldehyde and acetal copolymers derived from trioxane; polyestersobtained by the condensation of saturated or unsaturated anhydrides ordibasic acids, such as maleic, fumaric, itaconic or terephthalicanhydrides or fumaric, adipic, azaleic, sebacic or isophthalic acids,with a glycol such as propylene glycol, ethylene glycol, diethyleneglycol, neopentyl glycol or trimethylpentane diol; polyurethanes derivedfrom a glycol such as trimethyl propane glycol, butanediol, or a miXturethereof, or a polyol derived from a polyester, polyether or derivativeof polycaprolactone, with a polyisocyanate such as an aromatic oraliphatic diisocyanate or isocyanate-terminated prepolymer; andpolyamides such as polycaprolactam or those obtained by the condensationof hexamethylenediamine with adipic or sebacic acid or the like. Thecompounds of this invention are also useful for the stabilization ofnatural rubber; halogenated rubbers; polymers derived from conjugateddienes such as polybutadiene, copolymers of butadiene and styrene,acrylonitrile, acrylic acid, alkyl acrylates or methacrylates,methylvinyl ketone, vinyl pyridine and the like, polyisoprene orpolychloroprene; vinyl polymers such as polyvinyl chloride, polyvinylfluoride, polyvinylidene chloride, polyvinyl acetate copolymers of vinylchloride with vinylidine chloride, butadiene, styrene, vinyl esters,acrylic or methacrylic acid, or other a,,8-olefinically unsaturatedacids and esters thereof such as alkyl acrylates and methacrylates,a,5-olefinicially unsaturated ketones and aldehydes and the like;homopolymers and copolymers of acrylic monomers such as acrylic acid,methacrylic acid, methyl acrylate, methyl methacryllate, ethyl acrylate,2-ethylhexyl acrylate, acrylamide, methacrylamide, N-methylolacrylamide, acrylonitrile, methacrylonitrile or the like;polycarbonates; epoxy resins such as those obtained by the condensationof epichlorohydrin with bisphenols and copolymers of ethylene oxide orpropylene oxide with epichlorohydrin; and like polymeric compositions.In general, any polymeric system subject to degradation as a result ofoxidative, thermal or photochemical effects will be stabilized by theaddition of a small amount of the present compounds thereto.

In addition to the above-mentioned polymeric organic materials thealkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycles areuseful to stabilize nonpolymeric organic materials. Waxes, synthetic andpetroleum-derived lubricating oils and greases, mineral oils, fat,tallow, lard, codliver oil and sperm oil, vegetable oils such as castor,linseed, peanut, palm and cotton seed, fuel oil, diesel oil, gasolineand similar materials are effectively stabilized with the compounds ofthe present invention.

The compounds of the present invention are especially useful for thestabilization of a-monoolefin homopolymers, copolymers and terpolymers,polyacetal homopolymers and copolymers, polyamides, polyesters andpolyurethanes. Both high and low density polyethylene, polypropylene,polyisobutylene and p0ly-4-methyl-pentene-1 show markedly improvedresistance to oxidative, thermal and photochemical degradation whenstabilizing amounts of the present compounds are added thereto.Ethylenepropylene copolymers and ethylene-propylene terpolymers,containing less than about by weight of a third monomer containingmultiple unsaturation, are effectively stabilized with thealkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycles. Polymerblends of two or more copolymers or homopolymers derived froma-monoolefins are also stabilized in accordance with the presentinvention.

The amount of stabilizer employed will vary with the organic material tobe stabilized and the particularalkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle employed.In general, for effective stabilization of most organic materials anamount of alkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycleranging from about 0.001% to about 10% by weight based on the weight ofthe organic material will be employed. In most applications the amountof stabilizer will vary between about 0.01% and about 5% by weight. Whena-monoolefin, homopolymers, copolymers or terpolymers are to bestabilized, about 0.05% to about 2.5% by weight of thealkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycles will bemore useful in some applications than in others, any of the compounds ofthe present invention employed in an amount as defined above will be aneffective stabilizer for organic materials.

The compounds of this invention are readily incorporated into mostorganic materials and generally require no special processing.Conventional methods of incorporation have been found to be adequate.For example, the alkylhydroxyphenylcarboalkoxy-substituted nitrogenheterocycles can be incorporated into the polymers by mixing on a rubbermill or in a Banbury mixer or they may be added alone, in a suitablesolvent, or masterbatched with other compounding ingredients to asolution or dispersion of the polymer. The solubility of the presentcompounds in a wide variety of organic solvents facilitates their use insolution and also renders them compatible with most oils and lubricants.

The present compounds are compatible with conventional compoundingingredients such as processing oils, plasticizers, lubricants,anti-sticking agents, fillers, reinforcing agents, sulfur and othercuring agents, accelerators, anti-foaming agents, rust inhibitors andthe like. They are also compatible with other known antioxidants,antiozonants, color and heat stabilizers, ultraviolet absorbers and thelike, and when employed in combination with many of these a synergisticelfect will be obtained.

When the alkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocyclesare combined with peroxide decomposing compounds such asdithiocarbamates, zinc dialkylthiophosphates, phosphites such astris(p-nonylphenyl) phosphite and tridecylphosphite, organic sulfidesand similar sulfur-containing compounds, a marked increase in thestability of the resulting polymer composition over that obtained byemploying an identical amount of either stabilizer componentindividually is obtained.

Peroxide decomposing compounds such as the organic sulfides described inUS. Pat. No. 2,519,755 are advantageously employed in conjunction withthe novel compounds of this invention to give highly effectivesynergistic stabilizer compositions. Especially useful organic sulfidesare diesters of ,B-thiodipropionic acid having the formula wherein R isa hydrocarbon radical containing from about 6 to 20 carbon atoms such asoctyl, nonyl, decyl, lalllryl, cetyl, stearyl, palmityl, benzyl,cyclohexyl and the Also useful in combination with thealkylhydroxyphenylcarboalkoxy-substituted compounds of the presentinvention to obtain synergistic activity are thiopropionamides, that is,compounds containing one or more molecular groupings of the formulawherein R is a hydrogen or a methyl radical and R is a hydrocarbonradical containing from 1 to 24 carbon atoms. Such thiopropionamidecompounds include hisand tris-thiopropionamides such as described incopending application Ser. No. 873,650. Illustrative of usefulsulfur-containing compounds of the above type which may be used incombination with the alkylhydroxyphenylcarboalkoxy-substituted nitrogenheterocycles include N,N'-methylene-bis ,B- (octylthio propionamide]N,N'-methylene-bis [,8- (octylthio -a-methylpropionamide],

N,N-methylene-bis ,3- (dodecylthio propionamide] N,N-methylene-bis fi-(hexadecylthio propionamide] N,N'-methyl-ene-bis[B-(octadecylthio)-u-methylpropionamide],

hexahydro-1,3,5-tris [B-(octylthio) propionyl]-s-triazine,

hexahydro-1,3,5-tris[fi-(octylthio)-a-methylpropionyl] s-triazine,

hexahydro-1,3,5-tris [,6- (dodecylthio) propiony1]-striazine,

hexahydro- 1,3 ,5 -tris B- (octadecylthio) propionyl] -striazine,

hexahydro-l, 3,5-tris B- (octadecylthio -a-methy1- propionyl]-s-triazine,

hexahydro-1,3,5-tris[B-(phenylthio)propiony1]-striazine,

and the like.

Additionally, alkylcarboxyalkylthiopropionamides, that is,sulfur-containing compounds containing one or more groups having thestructural formula wherein R, is hydrogen or a methyl group, x is aninteger from 1 to 9 and R is a hydrocarbon radical containing from 1 to24 carbon atoms, may be advantageously employed in combination with thealkylhydroxyphenylcarboalkoxy-substituted compounds of the presentinvention. Specific alkylcarboxyalkylthiopropionamides which may beemployed include N,N'-methylene-bis [fln-dodecyl-Z-carboxyethylthio)propionamide],

N,N'-methylene-bis p- (n-do decyl-Z-carboxyethylthio-ocmethylpropionamide],

N,N'-methylene-bis[,6-(n-dodecylcarboxymethylthio)-amethylpropionamide],

N,N'-methylene-bis[5-(octadecyl-Z-carboxyethylthio) propionamide]N,N'-methylene-bis [[3- (ctadecyl-2-carboxyethylthio)-amethylpropionamide] hexahydro- 1,3 ,5 -tris ,6-(n-dodecyl-2-carboxyethy1thio) propionyl] -s-triazine, hexahydro- 1,3,5-tris (3- (n-dodecylcarboxymethylthio -amethylpropionyl] -s-triazine,

hexahydro- 1 ,3,5-tris 3-(hexadecyl-Z-carboxyethylthio)propionyl]-s-triazine,

hexahydr0-1,3,5-tris[[3-(octadecyl-2-carboxyethylthio) propionyl]-s-triazine,

hexahydro- 1,3,5 -tris (3- (octadecyl-2-carboxyethylthio)-amethylpropionyl]-s-triazine,

and the like.

When combinations of stabilizers are employed to obtain synergisticactivity, the total amount of the stabilizer combination will rangebetween about 0.01% and 5% by weight based on the polymer composition.Excellent results have been obtained when the total stabilizerconcentration is between about 0.1% and 2% by weight and the weightratio of the sulfur-containing compound to thealkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle is about1:1. The weight ratio of the two components can be varied between about5:1 and 1:5 and still obtain synergistic activity,

l C mHZm COOH wherein R and m are the same as defined above in FormulaI, is particularly convenient to prepare the present compounds. Theesterification reaction will generally be conducted with an acidiccatalyst in an inert solvent. The amounts of reactants employed will bedetermined by the degree of substitution desired and the particularnitrogen heterocycle to be substituted. For example, if atris(hydroxyalkyl)isocyanurate is to be completely substituted, threemols of the acid will be employed per mol of the isocyanuric acidderivative. If partial substitution of the nitrogen heterocycle isdesired, the amount of the acid reacted therewith will be decreasedproportionately in accordance with the desired degree of substitution.

The acid to be reacted may be obtained by any of the conventionalmethods including hydrolysis of an ester precursor. Similarly, thehydroxyalkyl-substituted nitrogen heterocycle may be obtained by avariety of methods depending on the particular hydroxyalkyl group to besubstituted. For example, hydroxymethyl groups may be substituted onisocyanuric acid or other nitrogen heterocycle by reaction withformaldehyde. Three mols of formaldehyde would be reacted with one molof cyanuric acid at an elevated temperature to obtaintris(hydroxymethyl) isocyanurate. Tris(2-hydroxyethyl)isocyanurate maybe obtained by the reaction of ethylene oxide and cyanuric acid indimethylformamide or dimethylacetamide. If long chain hydroxyalkylgroups are to be substituted they may be prepared by the proceduredescribed in U.S. Pat. No. 3,249,607.

The following examples serve to illustrate the invention more fully. Inthese examples all parts and percentages are on a weight basis unlessindicated otherwise. Parts of stabilizer are based on parts of polymer.Various terms used throughout the examples have been abbreviated forconvenience and these are as follows:

t-Bu=tertiary butyl sec-Bu=secondary butyl Me=methyl THPI=2,2',2" tris[3(3,5 di t butyl-4-hydroxyphenyl propionyloxy] ethylisocyanurate ExampleI THPI was prepared by the esterification of 3-(3,5-di-tbutyl 4hydroxyphenyDpropanoic acid with tris-(2-hydroxyethyl)isocyanurate. The3-(3,5-di-t-butyl-4-hydroxypheny1)pr0panoic acid was obtained by firstpreparing the corresponding methyl ester and then hydrolyzing the esterto the acid. To obtain the methyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propanoate, 66.2 grams (0.32 mol) 2,6- di-t-butylphenolwas reacted with 3.16 grams sodium methoxide in 250 mlsN,N-dimethylformamide which was previously dried by passing over 3 A.molecular sieves. The reactor and its contents were then heated forapproximately one hour at a maximum temperature of about C. to take 01fthe methanol. The reaction mixture was allowed to cool to about 35 C.and 25.1 grams (0.29 mol) methylacrylate charged. The reaction washeated for about 6 hours at reflux and then neutralized by the additionof hydrochloric acid (1:1 by volume). The N,N-dimethylformamide wasremoved by stripping under reduced pressure and about 90% yield of crudemethyl-3-(3,5-di-t-butyl 4 hydroxyphenyDpropanoate based on the amountof acrylate charged was obtained.

The crude reaction product was vacuum distilled at 180 C. and 0.3 mm.mercury to obtain puremethy1-3-(3,5-dit-butyl-4-hydroxyphenyl)propanoate melting at 62-63 C.

copy. Results of elemental analysis of the product are as follows:

Methyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propanoate Theory for obtainedfrom several runs as described above was hy- 5 cmHwNaom Found drolyzedto obtain the acid by dissolving about 920 grams Percent: 69 16 18methyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propanoate in 8:36 8.62 about10 kilograms of water containing about 460 mls. 3-22 2-22 methanol and175 grams sodium hydroxide. The reaction mixture was refluxed for aboutone hour the PH adjusted 10 Employing similar esterification proceduresto that de- 523295.; 33.13333211331856 gid lli ifii iilitiii niiifisewed above other alkylhydmxyphenylcarboallwxy-subture was refluxeduntil it was essentially colorless. 1:1 hyg ggg fgg gg fgg g g; 5 giggig drochloric acid was then added to reduce the pH to about 3 3 u a m g 2and precipitate the product. The resulting 3-(3,5-di-t- 15butyl-4-hydroxyphenyl)propanoic acid was washed and dried in a vacuumoven at 50 C. A 97% yield of the 3- N (3,5-di-t-butyl 4hydroxyphenyDpropanoic acid (M.P. 173174 C.) was obtained. I I

Esterification of the 3-(3,5-di-t-butyl-4-hydroxyphenyl) propanoic acidwith tris-(Z-hydroxyethyl)isocyanurate, 0 obtained by the reaction ofcyanuric acid with ethylene y, oxide in N,N-dimethylformamide asdescribed by R. W.

Cummins, J. Amer. Chem. Soc., 2s, 85 (1963), gives Wherem THPI in goodyield. The reaction was conducted in a 0 A 12-liter glass reactorequipped with a Dean-Stark water g trap by combining 157 grams (0.6 mol)tris-(2-hydroxy- R'=C.Hz.-o -c H2 0H ethyl)isocyanurate and 552 grams(1.98 mols; 10% molar 1g excess)3-(3,5-di-t-butyl-4-hydroxyphenyl)propanoic acid in three liters dryxylene. Hydrogen chloride was then Compounds set forth in Table I wereidentified by inbubbled into the reaction mixture until it was saturatedfrared spectroscopy, nuclear magnetic resonance spectrosand 5.53 gramsp-toluene sulfonic acid charged. The recopy and/or elemental analysis.

TABLE I Compound 10 y A B R R*" Formula 2 t-Bu t-Bu R R CwHstNaOn 2 t-But-Bu R R* CaaHasNsOm 2 t-Bu t-Bu R* R 72H1llN30l 2 t-Bu t-Bu -CH2CH2OH-CH2CH2OH CzaHasNaaoa 2 13-1311 t-Bll R CHzCHzOH C43Hs3N3010 2 t-Bu t-BuC 2CH2OC(Cl I2)1sCHa -CHzOH2OC !(CH2)1aCH g CwHmzNaOlo 0 2 t-Bu t-Bu R"-CHzCH2O( (CH2)1oCH.-4 Crs aaNaou 0 t-Bu t-Bu R R 54 7s a 12 3 t-Bu t-BuR R Cea oaNaOu 2 Me Me R R C42 siNaO1a 2 Me t-Bu R R C51 NaO12 2 ii-B11H R R CquHsaNaOlz 2 sec-Bu sec-Bu R* R Ceu a1NaOu 55 Example II 223?;fig g z figgg 3 32:? :8; 1 2: Employing a procedure similar to thatdescribed in Exmoved by azeotropic distillation, allowed to cool and23%;; gig ggi g g g ggi gig I 1 355533 $5. iifiiiiffiiiii riiiilf .ZZ.?$tt-.li. i m )Pmpanti? add with h-ydmxyethyl'mb' P g stitutedth1orsocyanurate compound obtained by the reacllke crude. Product T1115cfudfi PfQdllct was dlssolved 1H tron of trithlocyanuric acid with amolar excess of ethylabout 2 liters of diethyl ether and washed withseveral ene oxide in N,N-dimethylformamide at about 100 C. portions of0.5% aqueous sodium hydroxide until the E 1 HI wash had a pH of 10 orgreater and then with water. Xamp 6 After drying the ether was strippedunder vacuum and An alkylhyfir9xyphenylcarboalkoxysubsfituted deriva'about 95 yield THPI obtained as a crude glassy t1ve of phthalimide wasprepared in accordance with the terial having a softening point of about67 C. This ma- Procedure of Example I by the grams terial was furtherpurified by dissolving at 65-70 C. in (0'16 mol) ofN-(z-hydmwethyl)phthahmlde and about 5 liters heptane and allowing thesolution to cool gram-s (0315-11101)3-(35-dl-t-butyl-4Thydroxyphnyl)proto room temperature with vigorousagitation. 70 panolclfa C14 m i dry {Meme wlth gran-a ptolu' Byrecrystallization from isopropanol THPI is obtained ii fi g i gggglj roio fi figi 122 1 31: as a colorless crystalline material melting at 127C.- at 107.109 was obtained h Structure was 8 C- The product wasidentified as THPI by infrared firmed by nuclear magnetic resonancespectroscopy and inspectroscopy and nuclear magnetic resonancespectrosfrared spectroscopic analysis. Elemental analysis indicated 1 172.22% carbon, 7.41% hydrogen, 3.04% nitrogen and 17.33% oxygen to bepresent. Calculated for N-2-[3-(3,5- di-t-butyl 4hydroxyphenyl)propionyloxy]ethylphthalimide is 71.80% carbon, 7.37%hydrogen, 3.11% nitrogen and 17.72% oxygen.

Example IV Theory for CzaHaaNOs Found Percent:

Carbon 68. 40 68. 03 Hydrogen. 8. 49 8. 48 Nitrogen. 3.47 3. 42 Oxygen19. 85 19. 17

The crystalline material melted at 93.5 C.

Example V To demonstrate the utility of the THPI as a stabilizer fortat-olefin polymers, 100 parts high-density polyethylene was stabilizedwith 0.05 part THPI and compared against an unstabilized control bymeasuring the oxidation by difierential thermal analysis.

The oxidative stability of the various polymers was measured employing aditferential thermal analytical technique such as described by A. Rudinet al., Ind. & Eng. Chem, 53, No. 2, 137-140 (1961). This is a quick andconvenient method for determining the oxidation resistance of polymers.Stabilizers were incorporated into the polymer samples to be tested bypreparing a standard solution of the stabilizer in benzene, adding theproper volume of the standard solution to a known weight of the polymerso as to give the desired stabilizer level, and evaporating the benzeneby air drying. Two milligram samples are run in air and in nitrogen withthe instrument programmed to give a temperature rise of C./ minute. Fromthe resulting thermogram the oxidation exotherm can be observed. Thehigher the temperature at which the oxidation exotherm appears thegreater the oxidative resistance of the sample.

The unstabilized polyethylene sample had its oxidation exotherm at 200C. whereas the oxidation endotherm for the sample stabilized with 0.05part THPI appeared at 223 C.

To further demonstrate the etfectiveness of the THPI, it was comparedwith a well-known commercially available stabilizer material, Irganox1010. Irganox 1010 is sold by Geigy Chemical Corporation and istetra[methylene-3-(3,5 di-t-butyl-4-hydroxyphenyl)propionate]methane.High-density polyethylene stabilized with 0.05 part Irganox 1010 showedan oxidation exotherm at 220 C.

Example VI Polypropylene stabilized with 0.25 part THPI and tested inaccordance with the procedure described above in Example V had anoxidation exotherm of 227 C. Unstabilized polypropylene had itsoxidation exotherm of 176 C.

Polypropylene samples stabilized with THPI were also subjected tolong-term oven aging to demonstrate the effectiveness of the stabilizercompounds of the present invention by themselves and in combination withsulfurcontaining synergist compounds such as distearylthiodipropionate.To prepare the test samples polypropylene was dry blended with thestabilizers and then fluxed in an extruder at 450 F. The extrudate waspelletized and hot pressed at 420 F. into 10 mil thick specimens whichwere aged in an air-circulating oven at 150 C. The samples were deemedto have failed at the first sign of crazing. Test results for thevarious samples are tabulated below:

Example VII Ethylene-propylene terpolymer (53% ethylene, 43% propyleneand about 4% ethylidene norbornene) was stabilized with 0.3 part THPIand two other commercially available stabilizer compositions at the 0.3part level. Test samples were prepared by forming a 20% cement bydissolving the terpolymer and stabilizer in xylene and then casting afilm of the desired thickness on an infrared salt (KBr) plate byevaporation of the solvent. The specimens were aged in anair-circulating oven at C. and removed at regular intervals to measurethe development of the carbonyl content by infrared analysis. Thecarbonyl content is plotted versus aging time and failure of the sampleis marked by a sharp break in the curve. Testresults were as follows:

Stabilizer: Hours to failure None 1 THPI 22.8 n-Octadecyl-,8-(3,5di-t-butyl-4-hydroxyphenyl)propionate 4.7 Tetra [methylene-3-(3,5di-t-butyl-4-hydroxyphenyl)propionate]methane 16.8

The superior oxidati ve resistance of the samples stabilized with THPIis evident from the above data.

Example VIII One part THPI was incorporated in a synthetic naturalrubber composition (cis-polyisoprene) and the stabilized rubber testedin a -Brabender Plasticorder to measure the stability of the polymer.The stabilized polymer was placed in the heating chamber, heated at C.and the torque recorded. The time required for the torque to drop 1000units from the maximum (2500 units) was 7.5 minutes for the stabilizedsample. An unstabilized control ran for only 3 minutes.

Example IX A polymer blend of polyvinyl chloride,acrylonitrilebutadiene-styrene terpolymer and butadiene-nitrile polymerwas stabilized by the addition of 4 parts THPI and the polymer tested inaccordance with ASTM D-1925 6.3T for the development of the yellownessduring milling at 350 F. Initially both the unstabilized polymer blendand the stabilized polymer blend has a yellowness factor of 41. After 90minutes milling the unstabilized blend deteriorated to an 82 yellownessfactor while the stabilized composition only had a yellowness factor of67.

Example X THPI Was evaluated as an oxidation inhibitor in the ASTM D-943turbine-oil oxidation test and compared against an unstabilized sample.The turbine-oil was Texaco Regal Oil A, a 150 HVI neutral turbine oil.2.5% THPI plus 0.05% of a rust inhibitor, tetrapropenylsuccinicanhydride, were added to the oil. The stabilized turbine oil had a lifeof 525 hours whereas the unstabilized oil deteriorated within 24 hours.

Example XII A polyether-based urethane was stabilized with 0.5% THPI byadding the THPI to the polyol blend prior to heating to the reactiontemperature. The stabilized polyurethane had only a 60% decrease intensile strength after one week oven aging at 121 C. whereas anidentical unstabilized polyurethane showed a 77% decrease in tensilestrength after oven aging at 121 C. for one week.

Example XHI A plasticized high temperature polyvinyl chloride resinsuitable for wire and cable applications was stabilized by the additionof THPI and Bisphenol A. The resin and stabilizer were mixed in alaboratory Banbury at a temperature of 345 to 360 F. and then milled at310 F. for about minutes. Specimens were die-cut from 0.035 and 0.075sheets and pressed for 5 minutes at 345 F. between ferro-type plateswith approximately 1400 p.s.i. being applied on the platens. The sampleswere oven-aged at 158 C. for 7 days and the physical propertiesdetermined. Percent retention of elongation for the samples after agingwas as follows:

Two acrylic ester latices were stabilized by the addition of 0.5 partTHPI. Acrylic latex A contained about 95 parts ethyl acrylate and 3parts acrylonitrile with acrylic acid and N-methylol acrylamideinterpolymerized. Latex B contained a mixture of ethyl acrylate andn-butyl acrylate (85 parts) polymerized with 10 parts acrylonitrile andacrylamide. THPI was added to the latices as a 20% emulsion. Theresulting stabilized latices were then diluted to total solids and usedto saturate 10 mil bleached Kraft flat paper (Patterson Code 515) byimmersing the paper in the latex for seconds, dripdrying and curing for10 minutes. The papers were heataged at 300 F. in an air-circulatingoven and the percent reflectance, which is a measure of thediscoloration of the paper, measured at hour intervals. Initialreflectance readings before aging for both the stabilized andunstabilized saturated papers ranged between 77% and 78.5%. After hoursheat-aging the reflectance for the unstabilized paper saturated withLatex A was 27.5% as compared with 44.5% for the stabilized paper. Forthe papers saturated with Latex B, the reflectance for the paper coatedwith the unstabilized latex dropped to 40.5% after 25 hours agingwhereas the reflectance for the paper saturated with the stabilizedlatex was 59.9%.

Example XV A styrene-butadiene latex was stabilized by the addition ofTHPI to the latex (1.25 parts based on dry polymer). After coagulation,the crumbs were milled and 2" x 6" samples cut from the sheet for ovenaging at 105 C. Mooney viscosity data (ML 4-212 F.) indicated thatmarked improvement of the stability of the SBR samples stabilized withthe THPII over that of the unstabilized SBR. Similarly, markedsuperiority of the 14 stability of THPI stabilized SBR was observed overSBR stabilized with 1.25 parts Antioxidant 2246,2,2'-methylenebis-4-methyl-6-t-butylphenol sold by American CyanamidCompany. Similar improved stability was observed forbutadiene-acrylonitrile copolymer stabilized with THPI at a 2.5 partslevel.

Example XVI parts of polyvinyl chloride (Geon 101EP having a density of1.38) plasticized with about 50 parts dioctyl phthalate and containing 3parts stearic acid was oven aged at 325 F. The color tone of thespecimens was observed at 10-minute intervals. A marked improvement inthe resistance to discoloration was observed for the samples stabilizedwith the THPI as compared with unstabilized PVC samples.

Example XVII A natural rubber white stock was prepared in accordancewith the following recipe:

Ingredient: Parts Natural rubber 100 Stearic acid 2 Zinc oxide 5Titanium dioxide 50 Sulfur 2.75 Benzothiazyl disulfide 1Tetramethylthiuram disulfide 0.1 THPII 1 Example XVHI A copolymer ofethylene oxide and epichlorohydrin was compounded in a conventionalrecipe with zinc stearate, red lead and carbon black and stabilized with1 part THPI. The cured (30 minutes at 347 F.) composition was then airaged in a test tube for 168 hours at C. The stabilized compositionshowed a tensile loss of only 79% and a hardness loss of only 21 pointsafter aging. The unstabilized copolymer composition failed completelyunder these same test conditions.

Example XIX Other compositions stabilized with varying amounts of THPIare as follows:

Material: Parts of THPI Polystyrene 0.5 Neoprene sponge 1.0 Nylon 6 0.5Cyclohexene 0.001 Mineral oil 0.1 Polyoxymethylene 0.5 Polyethyleneterephthalate resin 0.5

All of these compostions showed improved oxidative stability over theunstabilized controls.

Example XX Unstabilized acetal copolymer resin obtained by polymerizingformaldehyde and ethylene oxide was tested for oxidative stabilityemploying the differential thermal technique previously described. Threelevels of THPI were employed. Since the acetal copolymer deteriorates intwo D epolyrnerization endotherm Oxidation exotherm 3-) 200 AbsentAbsent Absent Parts stabilizer Example XXI A series of stabilizedpolypropylene compositions were prepared and tested using thedifferential thermal analytical oxidation test method. All stabilizerswere employed at a 0.25 part level. The various stabilizer compounds areidentified by reference to the particular example in which they wereprepared. An unstabilized control and sample stabilized with a widelyknown commercial stabilizer composition were also included in the test.Test results are tabulated below.

CAO'1 is 4-n1ethyl-2,6-di-t-butyl-phenol sold by Hooker ChemicalCorporation.

Example XXII Polyacetal resin as described in Example XX was stabilizedwith 0.5 partN-2-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]ethylphthalimide and0.5 part N-2- [3(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]ethylsuccinimide asprepared in Examples III and IV. Oxidation resistance of the stabilizedsamples was markedly improved over that of the unstabilized control.Oxidation exotherrns for the stabilized samples were absent in bothcases while endothermic depolymerization did not occur until 225 C. and235 C., respectively.

It is evident from the above examples that the THPI and otheralkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycles of thepresent invention are effective stabilizer compounds for a Wide varietyof organic materials. By incorporating small amounts of the presentstabilizer into polymeric materials marked improvements in the oxidativestability of the polymers has been obtained.

We claim:

1. A stabilized composition of matter comprising an organic materialsubject to oxidative, thermal or photochemical degradation and about0.001% to about by weight based on the organic material of analkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocyclecomprising a heterocyclic compound of the formula RHI N wherein R is analkylhydroxyphenylcarboalkoxy group having the formula wherein n is aninteger from 1 to 12, m is an integer from 0 to 8 and R is selected fromthe group consisting of hydrogen, alkyl, cycloalkyl, phenyl, alkylphenyland phenylalkyl radicals containing from one to 12 carbon atoms; and R"and R' are the same as R or are selected from the group consisting ofhydrogen, alkyl, cycloalkyl, phenyl, alkylphenyl, phenylalkyl radicalscontaining 1 to 20 carbon atoms, a hydroxyalkyl group containing from 1to 12 carbon atoms and an alkylcarboalkoxy group containing 2 to 20carbon atoms.

2. A stabilized composition of matter of claim 1 wherein the organicmaterial is a polymeric material selected from the group consisting ofan u-monoolefin homopolymer, an a-Inonoolefin copolymer, an wmonoolefinterpolymer, a polyacetal homopolymer, a polyacetal copolymer, apolyamide, a polyester and a polyurethane.

3. The stabilized composition of matter of claim 2 wherein thealkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle ispresent in an amount between about 0.0l% and 5% by weight.

4. The stabilized composition of matter of claim 2 wherein the polymericmaterial is an a-monoolefin homopolymer, copolymer or terpolymer; R ofthe alkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycles hasthe formula 0 F ,1. L ,l L Zn-J 0 4 LC. Him-J I I wherein n and m' areintegers from 1 to 3, R and R are tertiary alkyl groups containing from4 to 8 carbon atoms and R is hydrogen; and thealkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle ispresent in an amount between about 0.05% and 2.5% by weight.

5. The stabilized composition of matter of claim 4 wherein thealkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle is2,2',2"-tris[3(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]ethylisocyanurate.

6. The stabilized composition of matter of claim 4 wherein there isadditionally present a peroxide decomposingcompound, the total amount ofstabilizer is between about 0.01% and 5% by weight based on the polymercomposition and the weight ratio of the peroxide decomposing compound tothe alkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle isbetween about 5:1 and 1:5.

7. The stabilized composition of matter of claim 6 wherein the peroxidedecomposing compound is a diester of p-thiodipropionic acid having theformula wherein R is a hydrocarbon radical containing from 6 to 20carbon atoms and the weight ratio of the peroxide decomposing compoundto the alkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle isabout 1:1.

8. The stabilized composition of matter of claim 7 wherein in thealkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycleR=R"'=R"'.

9. The stabilized composition of matter of claim 8 wherein the polymericmaterial is polyethylene or polypropylene and the total amount ofstabilizer is between about 0.1% and 2% by weight.

10. The stabilized composition of matter of claim 9 wherein thealkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle is2,2',2"-tris[3(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]ethylisocyanurateand the peroxide decomposing compound is dilaurylthiodipropionate ordistearylthiodipropionate.

11. A stabilized composition of matter comprising an organic materialsubject to oxidative, thermal or photochemical degradation and about0.001% to about 10% by weight based upon the organic material of ahydroxyphenylcarboalkoxy-substituted nitrogen heterocycle, the saidheterocycle compound containing one or more nitrogen atoms with twocarbonyl or thiocarbonyl groups immediately adjacent thereto in the ringselected from the group consisting of uric acid, hydantoin, allantoin,parabanic acid, alloxan, uracil, thymine, barbituric acid,phenobarbitone, succinirnide, maleimide, and phthalimide; andsubstituted at one or more nitrogen atoms With an alkylhydroxyphenylgroup of the formula wherein R is hydrogen or a hydrocarbon radicalcontaining from 1 to 12 carbon atoms, said alkylhydroxyphenyl groupbonded to the nitrogen atom of the heterocycle nucleus with acarboalkoxy group containing 2 to 20 carbon atoms.

12. A composition of claim 11 wherein in thealkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle the saidcarboalkoxy group has the formula wherein n is an integer from 1 to 12,m is an integer from to 8, R is hydrogen or an alkyl, cycloalkyl, aryl,alkaryl, or aralkyl radical containing from 1 to 12 carbon atoms.

13. A composition of claim 12 wherein thealkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle 18contains an alkylhydroxyphenylcarboalkoxy group having the formulawherein n' is an integer from 1 to 8, m is an integer from 1 to 4, R isan alkyl group containing from 1 to 8 carbon atoms and R and R arehydrogen or an alkyl group containing from 1 to 8 carbon atoms.

14. A composition of claim 13 wherein in thealkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle R is atertiary alkyl group containing from 4 to 8 carbon atoms, R is an alkylgroup containing from 1 to 8 carbon atoms and R is hydrogen.

15. A composition of claim 14 wherein in thealkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle R is atertiary alkyl group containing from 4 to 8 carbon atoms and n' and mare integers from 1 to 3.

16. A composition of claim 13 wherein the alkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle isN-2-[3-(3,5-di-t-butyl 4 hydroxyphenyl)propionyloxy]ethylphthalimide.

17. A composition of claim 13 wherein thealkylhydroxyphenylcarboalkoxy-substituted nitrogen heterocycle isN-2-[3-(3,5-di-t-butyl 4 hydroxyphenyDpropionyloxy] ethylsuccinimide.

References Cited UNITED STATES PATENTS 3,644,277 2/1972 Gilles 260-45.83,598,815 8/1971 Gilles 260-45 .8 3,637,582 1/ 1972 Gilles 260-4583,435,065 3/ 1969 Dexter et a1 260-45.8 3,644,482 2/ 1972 Dexter et al260-45.85 3,004,035 10/1961 Csendes 26045 .8 3,629,192 12/1971 Heller etal. 260-458 3,436,362 4/1969 Hayer et a1. 26045.8 3,394,102 7/1968Wakasa et al 260-45.8 3,360,520 12/ 1967 Luckenbaugh et a1. 260-4582,574,987 3/ 1950 Shelley 260-458 DONALD E. CZAJA, Primary Examiner E.C. RZUCIDLO, Assistant Examiner US. Cl. X.R.

252-405; 26045.8 NT, 45.85 B, 45.9

UNHED STATES PATENT oFmct QETEFEQATE CE QCECHN Patent No. 3,763, 093Dated oCtObeI' 973 George Kletecka and Peter D. Smith Inventor(s) It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

In Table I, Columns 9 and 10, the formula for Compound I(c) readingShOuld read the formula for Compound I(d) reading "C H N O should 5 andthe R** for Compound I(f) reading o H H "-cH cH 0o(cH cH should read -CHCH OC(CH CH Signed and sealed this 21st day of May 197A.

(SEAL) Atte st 2 9 C MARSHALL DAM-i Attesting Officer Foam po-wso(10-69) USCOMM oo'eoan P69 *4 us. covsrmuznr PRINHNG orrlc; T' 59o-ass-au Sommissioner of Patents. or

. FORM PO-IOSO (10-69) 3,763,093 Dated October 2, 1973 Patent No.

George Kletecka and Peter D. Smith Inventor(s) It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

In Table 1, Columns 9 and 10, the formula for Compound I(c) reading "c HN o should read --C H N O the formula for Compound I(d) reading C H N OY should read --C H N O8---5 and the R** for Compound I(f) reading 0 0II H -cH cH oc(cH cH should read ---cH cH oc(cH cH Signed and sealedthis 21st day of May l97h.

(SEAL) Attest:

Lam-JAR?) LEE-LnTCLLEJQJR. C. MARSHALL LAnl-E Attesting OfficerCommissioner of Patents USCOMM-DC seam-P69 9 U.S. GOVERNMENT PRINTINGOFFICE 559 0-355-334

